In mobile communications systems, smart-card applications are used to make a distinction in a mobile terminal device (ME=Mobile Equipment) between a so-called general apparatus part (mobile station) operating in a mobile network of a defined type and a separate network/customer-specific part, which is generally known as a so-called SIM card.
At present, the use of mobile equipment in a specific type of mobile network generally demands that the end user has a subscription, which identifies, among other things, the mobile network, in which the communication is take place and the individual settings relating to the subscription, Such as the operator setting and the subscriber identifier of the end user. According to the state of the art, the data are recorded on a small silicon chip, on which at least memory areas are arranged for recording the aforementioned settings and loading them into the mobile station being used, as well as a possible microcontroller operating as the processor unit. Such an entirety is generally called a SIM (Subscriber Identity Module). The SIM is usually placed on an easily-handled plastic base, the compact package thus formed being generally called a SIM card.
A generally compatible location is arranged for the SIM card in the mobile station ME, in which contacts studs are arranged to connect the card electrically to the mobile station. The general construction of the SIM card includes not only a possible microcontroller, but also various memory devices and auxiliary circuits, which relate to things such controlling data transfer and the power supply. All of these are connected to each other with the aid of a data-transfer channel (Bus), which permits communication between the different parts of the SIM card.
The microcontroller that may be located on the SIM card has its own operating system, of which, as is known, there are several different manufacturers. The functions incorporated in the operating system include the microcontroller's instruction set and file references for, among other things, reading, interpreting, and updating the network, terminal, and user parameters recorded in the memory devices. Usually, the memory devices of a SIM card comprise so-called ROM and RAM memories and an erasable and reprogrammable EEPROM address space, which does not lose the data recorded on it, even if the power supply to it is cut off at times.
During the initialization of the SIM card, the file system defined in the standard is created in the EEPROM address space, in which the operator-specific mobile network related settings, the PIN code identifying the user, the user's telephone number memory, and text messages, for example, are recorded. The hierarchic file system, which is formed like a tree, is uniquely standardized and its application branches can be followed to retrieve files from the address space, which can be regarded as the address of the memory location, in which unique data relating to a specific subscription or network function are stored. These data are recorded in such a way that they can be read and modified by all manufacturers' equipment, provided that the equipment operates in accordance with the relevant mobile network standards.
The SIM standards define such matters as the order and coding of the data, i.e. the significance of the bits, and the use of the data, i.e. in which situations the ME uses which data and how and when they are updated. Further, the standard defines reading and writing rights, such as ‘never’, ‘always when the user enters the PIN or PIN2 code’, or ‘only after authentication’ (in TETRA). SIM cards according to the known standard are generally used in different mobile networks (GSM, UMTS, CDMA, etc.). A SIM standard for the TETRA system also exists, but, as far as is known, cards according to it have not yet been introduced. This appears to be perhaps partly due to the fact that the TETRA system is at present mainly used by organizations, so that accurate identification of the user and the amount of communication are not of great practical importance, as they would be generally in commercial operator-run networks, particularly in the case of a private user.
The principles of the operation of the mobile station's interface (MMI=Man-Machine Interface) and of the mobile station ME vary greatly between different equipment manufacturers. Thus, at present the various equipment manufacturers have differing needs to record non-standard, proprietary and user or subscriber-specific data on SIM cards. However, in SIM cards according to the state of the art, there is no readiness according to the standard for defining and recording such proprietary data. However, it would be very useful to be able to transport the proprietary data, independently of the mobile station being used.
The state of the art for recording and transferring proprietary data between different mobile stations is represented by solutions, in which the mobile station uses specific fields of the files defined in the SIM-card standard. This in turn leads to the card-manufacturers' and operators' own special solutions. Methods provided by the SIM application toolkits can also be used for this purpose. These solutions, however, have the general disadvantage that each manufacturer has its own non-uniform, scaled solution for recording data, which is uneconomical and causes problems when changing SIM cards between different manufacturers' mobile stations. Further, the strong reliance of the markets on operators often ignores the point of view of the equipment manufacturer, because no solution is defined in the standard.
The state of the art is referred to in U. S. Pat. No. 5,864,757 (Parker), which discloses a locking and opening method for permitting a terminal to be used in the network of a set operator. The publication discloses the recording of a response on a SIM card in which the response is derived in an extremely complicated manner from data linked to the manufacturing batch of the terminal. In this case, no direct reference to proprietary data is even possible. The application of the invention is such that the motivation for arranging such recording lies specifically with the operator. The recording is therefore arranged to take place in the manner described above, which uses poorly scalable operator-specific solutions.